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Abstract:

Provided is an image capturing system including an image capturing section
that includes a plurality of first light receiving elements for receiving
light of a first wavelength region and a plurality of second light
receiving elements for receiving light of a second wavelength region, a
control section that causes to be generated, from a subject, light of a
different spectrum at a different timing for each of the first wavelength
region and the second wavelength region, and an image generating section
that generates an image from light of a first spectrum from the subject
received by the first light receiving elements at a predetermined timing,
and light of a second spectrum from the subject received by the second
light receiving elements at a timing other than the predetermined timing.

Claims:

1. An image capturing system comprising:an image capturing section that
includes a plurality of first light receiving elements for receiving
light of a first wavelength region and a plurality of second light
receiving elements for receiving light of a second wavelength region;a
control section that causes to be generated, from a subject, light of a
different spectrum at a different timing for each of the first wavelength
region and the second wavelength region; andan image generating section
that generates a first image from a combination that includes at least
one of light of a first spectrum from the subject received by the
plurality of first light receiving elements at a predetermined timing,
light of a second spectrum from the subject received by the plurality of
second light receiving elements at the predetermined timing, light of a
third spectrum from the subject received by the plurality of first light
receiving elements at a timing other than the predetermined timing, and
light of a fourth spectrum from the subject received by the plurality of
second light receiving elements at the timing other than the
predetermined timing, and generates a second image from a combination
different from the combination used to generate the first image.

2. The image capturing system according to claim 1, whereinthe control
section causes to be generated, from the subject, light of a first
partial wavelength region included in the first wavelength region and
light of a second partial wavelength region included in the second
wavelength region at the predetermined timing, and causes to be
generated, from the subject, light of a third partial wavelength region
included in the first wavelength region and light of a fourth partial
wavelength region included in the second wavelength region at the timing
other than the predetermined timing, andthe image generating section
generates the first image from a combination that includes at least one
of light of the first partial wavelength region from the subject received
by the plurality of first light receiving elements at the predetermined
timing, the light of the third partial wavelength region from the subject
received by the plurality of first light receiving elements at the timing
other than the predetermined timing, the light of the second partial
wavelength region from the subject received by the plurality of second
light receiving elements at the predetermined timing, and the light of
the fourth partial wavelength region from the subject received by the
plurality of second light receiving elements at the timing other than the
predetermined timing.

3. The image capturing system according to claim 2, further comprising:a
light emission section that causes to be emitted, from the subject, light
of the first partial wavelength region, the second partial wavelength
region, the third partial wavelength region, and the fourth partial
wavelength region, whereinthe control section controls the light emission
section to emit the light which causes the light of the first partial
wavelength region and the light of the second partial wavelength region
emitting from the subject at the predetermined timing, and controls the
light emission section to emit the light of the third partial wavelength
region and the light of the fourth partial wavelength region from the
subject at the timing other than the predetermined timing.

4. The image capturing system according to claim 2, whereinthe light
emission section emits the light of the first partial wavelength region,
the second partial wavelength region, the third partial wavelength
region, and the fourth partial wavelength region,the control section
controls the light emission section to emit the light of the first
partial wavelength region and the light of the second partial wavelength
region towards the subject at the predetermined timing, and controls the
light emission section to emit the light of the third partial wavelength
region and the light of the fourth partial wavelength region towards the
subject at the timing other than the predetermined timing,at the
predetermined timing, the plurality of first light receiving elements
receive the light of the first partial wavelength region reflected from
the subject, and the plurality of second light receiving elements receive
the light of the second partial wavelength region reflected from the
subject, andat the timing other than the predetermined timing, the
plurality of first light receiving elements receive the light of the
third partial wavelength region reflected from the subject, and the
plurality of second light receiving elements receive the light of the
fourth partial wavelength region reflected from the subject.

5. The image capturing system according to claim 3, whereinthe image
generating section generates a composite image by combining the first
image and the second image.

6. The image capturing system according to claim 5, whereinthe image
generating section generates the second image, from the light of the
first partial wavelength region received by the plurality of first light
receiving elements at the predetermined timing, the light of the third
partial wavelength region received by the plurality of first light
receiving elements at the timing other than the predetermined timing, the
light of the second partial wavelength region received by the plurality
of second light receiving elements at the predetermined timing, and the
light of the fourth partial wavelength region received by the plurality
of second light receiving elements at the timing other than the
predetermined timing.

7. The image capturing system according to claim 6, whereinthe image
generating section generates the composite image by overlapping the first
image onto the second image with an emphasis on the first image.

8. The image capturing system according to claim 6, further comprising:an
output section that outputs the first image and the second image
generated by the image generating section, in association with each
other.

9. The image capturing system according to claim 6, whereinthe image
generating section generates the second image based on a) a summation,
for each first light receiving element, of an amount of light of the
first partial wavelength region received by the plurality of first light
receiving elements at the predetermined timing and an amount of light of
the third partial wavelength region received by the plurality of first
light receiving elements at the timing other than the predetermined
timing, and b) a summation, for each second light receiving element, of
an amount of light of the second partial wavelength region received by
the plurality of second light receiving elements at the predetermined
timing and an amount of light of the fourth partial wavelength region
received by the plurality of second light receiving elements at the
timing other than the predetermined timing.

10. The image capturing system according to claim 9, whereinthe plurality
of first light receiving elements and the plurality of second light
receiving elements receive the light emitted by the light emission
section after being reflected from an object existing inside a
substance,the first wavelength region that is shorter than the second
wavelength region,the first partial wavelength region and the second
partial wavelength region are shorter than the third partial wavelength
region, at the predetermined timing, andthe first image represents an
image of an object existing at a shallower position from a surface of the
substance, and the image generating section generates the first image
based at least on the light of the first partial wavelength region
received by the plurality of first light receiving elements at the
predetermined timing.

11. The image capturing system according to claim 10, whereinthe first
partial wavelength region is shorter than the third partial wavelength
region and the second partial wavelength region is longer than the fourth
partial wavelength region, at the predetermined timing, andthe first
image represents an image of an object existing at a shallower position
from the surface of the substance and an object existing at a deeper
position from the surface of the substance, and the image generating
section generates the first image based at least on the light of the
first partial wavelength region received by the plurality of first light
receiving elements at the predetermined timing and the light of the
second partial wavelength region received by the plurality of second
light receiving elements at the predetermined timing.

12. The image capturing system according to claim 9, whereinthe plurality
of first light receiving elements and the plurality of second light
receiving elements receive the light emitted by the light emission
section after being reflected from an object existing inside a
substance,the first wavelength region is longer the second wavelength
region,the first partial wavelength region and the second partial
wavelength region are longer than the third partial wavelength region, at
the predetermined timing, andthe first image represents an image of an
object existing at a deeper position from a surface of the substance, and
the image generating section generates the first image based at least on
the light of the first partial wavelength region received by the
plurality of first light receiving elements at the predetermined timing.

13. The image capturing system according to claim 3, further comprising:a
first spectral filter that transmits the light of the first partial
wavelength region and the light of the third partial wavelength region;
anda second spectral filter that transmits the light of the second
partial wavelength region and the light of the fourth partial wavelength
region, whereinthe plurality of first light receiving elements receive
light from the subject after being transmitted through the first spectral
filter, and the plurality of second light receiving elements receive
light from the subject after being transmitted through the second
spectral filter.

14. The image capturing system according to claim 3, whereinthe light
emission section includes a plurality of light emitting elements that
respectively emit light of a different spectrum from each other, andthe
control section controls the light emission at the predetermined timing
and at the timing other than the predetermined timing by controlling
respective light emission intensities of the plurality of light emitting
elements.

15. The image capturing system according to claim 3, further comprising:an
irradiation light filter that transmits the light of the first partial
wavelength region and the light of the second partial wavelength region,
whereinthe light emission section emits light of a wavelength region, the
wavelength region including the first partial wavelength region, the
second partial wavelength region, and at least one of the third partial
wavelength region and the fourth partial wavelength region, andthe
control section controls the light from the light emission section to
irradiate the subject after being transmitted through the irradiation
light filter, at the predetermined timing.

16. The image capturing system according to claim 2, whereinthe image
generating section includes:a motion specifying section that specifies a
motion of an object in an image at a plurality of timings including the
predetermined timing, based on a plurality of images generated by a) the
light of the first partial wavelength region received by the plurality of
first light receiving elements at the plurality of timings and b) the
light of the second partial wavelength region received by the plurality
of second light receiving elements at the plurality of timings, anda
corrected image generating section that generates a corrected image which
is an image of a subject generated by the light of the first partial
wavelength region and the light of the second partial wavelength region
at the timing other than the predetermined timing, based on the light of
the first wavelength region received by the plurality of first light
receiving elements at the predetermined timing and the light of the
second wavelength region received by the plurality of second light
receiving elements at the predetermined timing.

17. The image capturing system according to claim 16, whereinthe image
generating section further includes:a subject image generating section
that generates the second image based on the corrected image and on an
image generated by the light of the third partial wavelength region
received by the plurality of first light receiving elements at the timing
other than the predetermined timing and the light of the fourth partial
wavelength region received by the plurality of second light receiving
elements at the timing other than the predetermined timing.

18. The image capturing system according to claim 4, whereinthe image
capturing section further includes a plurality of third light receiving
elements for receiving light of a third wavelength region,the light
emission section emits light of a fifth partial wavelength region and a
sixth partial wavelength region included in the third wavelength
region,the control section controls the light emission section to emit
the light of the first partial wavelength region, the light of the second
partial wavelength region, and the light of the fifth partial wavelength
region towards the subject at the predetermined timing, and to emit the
light of the third partial wavelength region, the light of the fourth
partial wavelength region, and the light of the sixth partial wavelength
region towards the subject at the timing other than the predetermined
timing,at the predetermined timing, the plurality of first light
receiving elements receive the light of the first partial wavelength
region reflected from the subject, the plurality of second light
receiving elements receive the light of the second partial wavelength
region reflected from the subject, and the plurality of third light
receiving elements receive the light of the fifth partial wavelength
region reflected from the subject, and at the timing other than the
predetermined timing, the plurality of first light receiving elements
receive the light of the third partial wavelength region reflected from
the subject, the plurality of second light receiving elements receive the
light of the fourth partial wavelength region reflected from the subject,
and the third light receiving elements receive the light of the sixth
partial wavelength region reflected from the subject, andthe image
generating section generates a first image from a combination that
includes at least one of the light of the first partial wavelength region
received by the plurality of first light receiving elements at the
predetermined timing, the light of the third partial wavelength region
received by the plurality of first light receiving elements at the timing
other than the predetermined timing, the light of the second partial
wavelength region received by the plurality of second light receiving
elements at the predetermined timing, the light of the fourth partial
wavelength region received by the plurality of second light receiving
elements at the timing other than the predetermined timing, the light of
the fifth partial wavelength region received by the plurality of third
light receiving elements at the predetermined timing, and the light of
the sixth partial wavelength region received by the plurality of third
light receiving elements at the timing other than the predetermined
timing, and generates a second image from a combination different from
the combination used to generate the first image.

19. The image capturing system according to claim 18, whereinthe first
wavelength region is a blue wavelength region, the second wavelength
region is a red wavelength region, and the third wavelength region is a
green wavelength region.

20. An image capturing method comprising:image capturing including a
plurality of first light receiving elements for receiving light of a
first wavelength region and a plurality of second light receiving
elements for receiving light of a second wavelength region;controlling to
cause to be generated, from a subject, light of a different spectrum at a
different timing for each of the first wavelength region and the second
wavelength region;image generating a first image from a combination that
includes at least one of light of a first spectrum from the subject
received by the plurality of first light receiving elements at a
predetermined timing, light of a second spectrum from the subject
received by the plurality of second light receiving elements at the
predetermined timing, light of a third spectrum from the subject received
by the plurality of first light receiving elements at a timing other than
the predetermined timing, and light of a fourth spectrum from the subject
received by the plurality of second light receiving elements at the
timing other than the predetermined timing, and generating a second image
from a combination different from the combination used to generate the
first image.

21. A computer readable medium storing thereon a program for an image
capturing system, the program causing the image capturing system to
function as:an image capturing section that includes a plurality of first
light receiving elements for receiving light of a first wavelength region
and a plurality of second light receiving elements for receiving light of
a second wavelength region;a control section that causes to be generated,
from a subject, light of a different spectrum at a different timing for
each of the first wavelength region and the second wavelength region;
andan image generating section that generates a first image from a
combination that includes at least one of light of a first spectrum from
the subject received by the plurality of first light receiving elements
at a predetermined timing, light of a second spectrum from the subject
received by the plurality of second light receiving elements at the
predetermined timing, light of a third spectrum from the subject received
by the plurality of first light receiving elements at a timing other than
the predetermined timing, and light of a fourth spectrum from the subject
received by the plurality of second light receiving elements at the
timing other than the predetermined timing, and generates a second image
from a combination different from the combination used to generate the
first image.

Description:

CROSS REFERENCE TO RELATED APPLICATION

[0001]The present application claims priority from a Japanese Patent
Applications No. 2007-292507 filed on Nov. 9, 2007 and No. 2008-271366
filed on Oct. 21, 2008, the contents of which are incorporated herein by
reference.

BACKGROUND

[0002]1. Technical Field

[0003]The present invention relates to an image capturing system, an image
capturing method, and a computer readable medium storing thereon a
program. In particular, the present invention relates to an image
capturing system, an image capturing method for capturing an image, and a
computer readable medium for storing thereon a program used in the image
capturing system.

[0004]2. Description of the Related Art

[0005]An electronic endoscope system capable of capturing an image of
tissues to be observed existing under an living organism is known, for
example by Japanese Patent Application Publication No. 2007-54113. In
addition, an image capturing apparatus that captures an optical image
based on re-radiation light emitted from a portion to be observed in
response to irradiation of light thereto is also known, for example as
disclosed in Japanese Patent Application Publication No. 2002-345733.

SUMMARY

[0006]Based on the technology of Japanese Patent Application Publication
No. 2007-54113, it is impossible to capture a visible light image with
high sensitivity, since there are a plurality of B pixels for receiving
light from different wavelength regions. In addition, based on the
invention of Japanese Patent Application Publication No. 2002-345733, it
is impossible to obtain an image of a narrow bandwidth. According to both
of the above prior art technologies, it is impossible to provide an image
of a desirable bandwidth and an image to be observed, by a simple
configuration.

[0007]In view of the above, according to an aspect of the innovations
herein, provided is an image capturing system including: an image
capturing section that includes a plurality of first light receiving
elements for receiving light of a first wavelength region and a plurality
of second light receiving elements for receiving light of a second
wavelength region; a control section that causes light of a different
spectrum at a different timing for each of the first wavelength region
and the second wavelength region; and an image generating section that
generates a first image from a combination that includes at least one of
light of a first spectrum from the subject received by the plurality of
first light receiving elements at a predetermined timing, light of a
second spectrum from the subject received by the plurality of second
light receiving elements at the predetermined timing, light of a third
spectrum from the subject received by the plurality of first light
receiving elements at a timing other than the predetermined timing, and
light of a fourth spectrum from the subject received by the plurality of
second light receiving elements at the timing other than the
predetermined timing, and generates a second image from a combination
different from the combination used to generate the first image.

[0008]An arrangement is possible in which the control section causes to be
generated, from the subject, light of a first partial wavelength region
included in the first wavelength region and light of a second partial
wavelength region included in the second wavelength region, and causes to
be generated, from the subject, light of a third partial wavelength
region included in the first wavelength region and light of a fourth
partial wavelength region included in the second wavelength region, and
the image generating section generates the first image from a combination
that includes at least one of light of the first partial wavelength
region from the subject received by the plurality of first light
receiving elements at the predetermined timing, the light of the third
partial wavelength region from the subject received by the plurality of
first light receiving elements at the timing other than the predetermined
timing, the light of the second partial wavelength region from the
subject received by the plurality of second light receiving elements at
the predetermined timing, and the light of the fourth partial wavelength
region from the subject received by the plurality of second light
receiving elements at the timing other than the predetermined timing, and
generates the second image from a combination different from the
combination used to generate the first image.

[0009]The image capturing system may further include a light emission
section that causes to emit, from the subject, light of the first partial
wavelength region, the second partial wavelength region, the third
partial wavelength region, and the fourth partial wavelength region,
where the control section controls the light emission section to emit the
light of the first partial wavelength region and the light of the second
partial wavelength region from the subject at the predetermined timing,
and that controls the light emission section to emit the light of the
third partial wavelength region and the light of the fourth partial
wavelength region from the subject at the timing other than the
predetermined timing.

[0010]An arrangement is possible in which the light emission section emits
the light of the first partial wavelength region, the second partial
wavelength region, the third partial wavelength region, and the fourth
partial wavelength region, the control section controls the light
emission section to emit the light of the first partial wavelength region
and the light of the second partial wavelength region towards the subject
at the predetermined timing, and that controls the light emission section
to emit the light of the third partial wavelength region and the light of
the fourth partial wavelength region towards the subject at the timing
other than the predetermined timing, at the predetermined timing, the
plurality of first light receiving elements receive the light of the
first partial wavelength region reflected from the subject, and the
plurality of second light receiving elements receive the light of the
second partial wavelength region reflected from the subject, and at the
timing other than the predetermined timing, the plurality of first light
receiving elements receive the light of the third partial wavelength
region reflected from the subject, and the plurality of second light
receiving elements receive the light of the fourth partial wavelength
region reflected from the subject.

[0011]An arrangement is possible in which the image generating section
generates a composite image by combining the first image and the second
image. An arrangement is possible in which the image generating section
generates the second image representing an image of the subject, from the
light of the first partial wavelength region received by the plurality of
first light receiving elements at the predetermined timing, the light of
the third partial wavelength region received by the plurality of first
light receiving elements at the timing other than the predetermined
timing, the light of the second partial wavelength region received by the
plurality of second light receiving elements at the predetermined timing,
and the light of the fourth partial wavelength region received by the
plurality of second light receiving elements at the timing other than the
predetermined timing.

[0012]The image generating section may generate a composite image by
overlapping the first image onto the second image with an emphasis on the
first image. The image capturing system may further include an output
section that outputs the first image and the second image generated by
the image generating section, in association with each other.

[0013]The image generating section may generate the second image based on
a summation, for each first light receiving element, of an amount of
light of the first partial wavelength region received by the plurality of
first light receiving elements at the predetermined timing and an amount
of light of the third partial wavelength region received by the plurality
of first light receiving elements at the timing other than the
predetermined timing, and on a summation, for each second light receiving
element, of an amount of light of the second partial wavelength region
received by the plurality of second light receiving elements at the
predetermined timing and an amount of light of the fourth partial
wavelength region received by the plurality of second light receiving
elements at the timing other than the predetermined timing.

[0014]An arrangement is possible in which the plurality of first light
receiving elements and the plurality of second light receiving elements
receive the light emitted by the light emission section after being
reflected from an object existing inside a substance, the plurality of
first light receiving elements receive the light of the first wavelength
region that is shorter than the second wavelength region, the control
section controls the light emission section to emit the light of the
first partial wavelength region and of the second partial wavelength
region that are shorter than the third partial wavelength region, at the
predetermined timing, and the image generating section generates the
first image representing an image of an object existing at a shallower
position from a surface of the substance based at least on the light of
the first partial wavelength region received by the plurality of first
light receiving elements at the predetermined timing.

[0015]An arrangement is possible in which the control section controls the
light emission section to emit the light of the first partial wavelength
region shorter than the third partial wavelength region and the light of
the second partial wavelength region longer than the fourth partial
wavelength region, at the predetermined timing, and the image generating
section generates the first image representing an image of an object
existing at a shallower position from the surface of the substance and an
object existing at a deeper position from the surface of the substance,
based at least on the light of the first partial wavelength region
received by the plurality of first light receiving elements at the
predetermined timing and the light of the second partial wavelength
region received by the plurality of second light receiving elements at
the predetermined timing.

[0016]An arrangement is possible in which the plurality of first light
receiving elements and the plurality of second light receiving elements
receive the light emitted by the light emission section after being
reflected from an object existing inside a substance, the plurality of
first light receiving elements receive the light of the first wavelength
region that is longer the second wavelength region, the control section
controls the light emission section to emit the light of the first
partial wavelength region and of the second partial wavelength region
that are longer than the third partial wavelength region, at the
predetermined timing, and the image generating section generates the
first image representing an image of an object existing at a deeper
position from a surface of the substance based at least on the light of
the first partial wavelength region received by the plurality of first
light receiving elements at the predetermined timing.

[0017]The image capturing system may further include a first spectral
filter that transmits the light of the first partial wavelength region
and the light of the third partial wavelength region; and a second
spectral filter that transmits the light of the second partial wavelength
region and the light of the fourth partial wavelength region, where the
plurality of first light receiving elements receive light from the
subject after being transmitted through the first spectral filter, and
the plurality of second light receiving elements receive light from the
subject after being transmitted through the second spectral filter.

[0018]An arrangement is possible in which the light emission section
includes a plurality of light emitting elements that respectively emit
light of a different spectrum from each other, and the control section
controls the light emission at the predetermined timing and at the timing
other than the predetermined timing by controlling respective light
emission intensities of the plurality of light emitting elements.

[0019]The image capturing system may further include an irradiation light
filter that transmits the light of the first partial wavelength region
and the light of the second partial wavelength region, where the light
emission section emits light of a wavelength region, the wavelength
region including the first partial wavelength region, the second partial
wavelength region, and at least one of the third partial wavelength
region and the fourth partial wavelength region, and the control section
controls the light from the light emission section to irradiate the
subject after being transmitted through the irradiation light filter, at
the predetermined timing.

[0020]An arrangement is possible in which the image generating section
includes: a motion specifying section that specifies a motion of an
object on an image among the plurality of timings, based on a plurality
of images, the plurality of images being generated by the light of the
first partial wavelength region received by the plurality of first light
receiving elements at a plurality of timings including the predetermined
timing and the light of the second partial wavelength region received by
the plurality of second light receiving elements at the plurality of
timings, and a corrected image generating section that generates a
corrected image which is an image of a subject generated by the light of
the first partial wavelength region and the light of the second partial
wavelength region at the timing other than the predetermined timing,
based on the light of the first wavelength region received by the
plurality of first light receiving elements at the predetermined timing
and the light of the second wavelength region received by the plurality
of second light receiving elements at the predetermined timing.

[0021]An arrangement is possible in which the image generating section
further includes: a subject image generating section that generates the
second image based on the corrected image and an image generated by the
light of the third partial wavelength region received by the plurality of
first light receiving elements at the timing other than the predetermined
timing and the light of the fourth partial wavelength region received by
the plurality of second light receiving elements at the timing other than
the predetermined timing.

[0022]An arrangement is possible in which the image capturing section
further includes a plurality of third light receiving elements for
receiving light of a third wavelength region, the light emission section
emits light of the first partial wavelength region, the second partial
wavelength region, the third partial wavelength region, the fourth
partial wavelength region, and a fifth partial wavelength region and a
sixth partial wavelength region included in the third wavelength region,
the control section controls the light emission section to emit the light
of the first partial wavelength region, the light of the second partial
wavelength region, the light of the fifth partial wavelength region to
the subject at the predetermined timing, and to emit the light of the
third partial wavelength region, the light of the fourth partial
wavelength region, and the light of the sixth partial wavelength region
to the subject at the timing other than the predetermined timing, at the
predetermined timing, the plurality of first light receiving elements
receive the light of the first partial wavelength region reflected from
the subject, the plurality of second light receiving elements receive the
light of the second partial wavelength region reflected from the subject,
and the plurality of third light receiving elements receive the light of
the fifth partial wavelength region reflected from the subject, and at
the timing other than the predetermined timing, the plurality of first
light receiving elements receive the light of the third partial
wavelength region reflected from the subject, the plurality of second
light receiving elements receive the light of the fourth partial
wavelength region reflected from the subject, and the third light
receiving elements receive the light of the sixth partial wavelength
region reflected from the subject, and the image generating section
generates a first image from a combination that includes at least one of
the light of the first partial wavelength region received by the
plurality of first light receiving elements at the predetermined timing,
the light of the third partial wavelength region received by the
plurality of first light receiving elements at the timing other than the
predetermined timing, the light of the second partial wavelength region
received by the plurality of second light receiving elements at the
predetermined timing, the light of the fourth partial wavelength region
received by the plurality of second light receiving elements at the
timing other than the predetermined timing, the light of the fifth
partial wavelength region received by the plurality of third light
receiving elements at the predetermined timing, and the light of the
sixth partial wavelength region received by the plurality of third light
receiving elements at the timing other than the predetermined timing, and
generates a second image from a combination different from the
combination used to generate the first image.

[0023]An arrangement is possible in which the first wavelength region is a
blue wavelength region, the second wavelength region is a red wavelength
region, and the third wavelength region is a green wavelength region.

[0024]According to a second aspect of the innovations herein, provided is
an image capturing method including: image capturing including a
plurality of first light receiving elements for receiving light of a
first wavelength region and a plurality of second light receiving
elements for receiving light of a second wavelength region; controlling
to cause, to be generated from a subject, light of a different spectrum
at a different timing for each of the first wavelength region and the
second wavelength region; image generating to generate a first image from
a combination that includes at least one of light of a first spectrum
from the subject received by the plurality of first light receiving
elements at a predetermined timing, light of a second spectrum from the
subject received by the plurality of second light receiving elements at
the predetermined timing, light of a third spectrum from the subject
received by the plurality of first light receiving elements at a timing
other than the predetermined timing, and light of a fourth spectrum from
the subject received by the plurality of second light receiving elements
at the timing other than the predetermined timing, and to generate a
second image from a combination different from the combination used to
generate the first image.

[0025]According to a third aspect of the innovations herein, provided is a
computer readable medium storing thereon a program for an image capturing
system, the program functioning the image capturing system as: an image
capturing section that includes a plurality of first light receiving
elements for receiving light of a first wavelength region and a plurality
of second light receiving elements for receiving light of a second
wavelength region; a control section that causes to be generated, from a
subject, light of a different spectrum at a different timing for each of
the first wavelength region and the second wavelength region; and an
image generating section that generates a first image from a combination
that includes at least one of light of a first spectrum from the subject
received by the plurality of first light receiving elements at a
predetermined timing, light of a second spectrum from the subject
received by the plurality of second light receiving elements at the
predetermined timing, light of a third spectrum from the subject received
by the plurality of first light receiving elements at a timing other than
the predetermined timing, and light of a fourth spectrum from the subject
received by the plurality of second light receiving elements at the
timing other than the predetermined timing, and generates a second image
from a combination different from the combination used to generate the
first image.

[0026]The summary of the invention does not necessarily describe all
necessary features of the present invention. The present invention may
also be a sub-combination of the features described above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 shows an exemplary configuration of an image capturing system
10 of the present embodiment, together with an analyte 20.

[0029]FIG. 3 shows an exemplary spectral sensitivity characteristic of a
light receiving element, and an exemplary spectral reflectivity of a
surface layer of a living organism that is one example of a target of
which the image is to be captured.

[0034]FIG. 8 explains generation of a visible light image in which the
motion is corrected.

[0035]FIG. 9 shows an example of a spectral sensitivity characteristic of
a light receiving element and a configuration of the light source filter
420.

[0036]FIG. 10 shows an example of an image capturing timing of the image
capturing section 110 and an image generated by an image generating
section 140.

[0037]FIG. 11 shows an exemplary hardware configuration of a computer 1500
that functions as an image capturing system 10.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0038]The invention will now be described based on the preferred
embodiments, which do not intend to limit the scope of the present
invention, but exemplify the invention. All of the features and the
combinations thereof described in the embodiment are not necessarily
essential to the invention.

[0039]FIG. 1 shows an exemplary configuration of an image capturing system
10 of the present embodiment, together with an analyte 20. The image
capturing system 10 includes an endoscope 100, an image generating
section 140, an output section 180, a control section 105, a light
irradiation section 150, and an ICG injection section 190. Note that
Section A in FIG. 1 is an enlarged view of a tip 102 of the endoscope
100.

[0040]The ICG injection section 190 injects, to the analyte 20 which is an
example of a subject, indocyanine green (ICG) which is a luminescence
substance. Although ICG is used as a luminescence substance in the
present embodiment, a fluorescent substance other than ICG may also be
used as a luminescence substance.

[0041]ICG emits fluorescence of a broad spectrum centering around 810 nm,
by being excited by infrared light of a wavelength of 750 nm for example.
When the analyte 20 is a living organism, the ICG injection section 190
injects ICG to the blood vessels of the living organism by means of
intravenous injection. The image capturing system 10 captures the image
of the blood vessels within the living organism using luminescence light
from the ICG. Note that the luminescence light is one example of light in
a specific wavelength region, and includes fluorescence and phosphor.
Note that the luminescence light which is an example of light from a
subject includes luminescence light of chemical luminescence,
triboluminescence, and thermal luminescence, other than light
luminescence of excitation light.

[0042]The ICG injection section 190 injects ICG to the analyte 20 so that
the ICG concentration within the living organism is maintained
substantially constant, by means of control performed by the control
section 105 for example. Note that the analyte 20 may be a living
organism such as a human body, and the captured image of the analyte 20
is to be processed by the image capturing system 10. Note that an object
such as a blood vessel exists in the analyte 20.

[0043]The endoscope 100 includes an image capturing section 110, a light
guide 120, and a clamp port 130. The tip 102 of the endoscope 100 is
provided with an objective lens 112 as part of the image capturing
section 110. The tip 102 is also provided with an outlet 124 as part of
the light guide 120. The tip 102 of the endoscope 100 is provided with a
nozzle 138.

[0044]A clamp 135 is inserted into the clamp port 130, and the clamp port
130 guides the clamp 135 towards the tip 102. Note that the form of the
tip of the clamp 135 may be varied. Various types of treatment equipment
may be inserted into the clamp port 130 other than a clamp, for the
purpose of treating a living organism. The nozzle 138 sends out water or
air.

[0045]The light irradiation section 150 generates light to be irradiated
from the tip 102 of the endoscope 100. The light generated by the light
irradiation section 150 includes infrared light which is an example of
excitation light of a wavelength region capable of exciting the
luminescence substance included in the analyte 20 thereby causing light
of the specific wavelength region, and irradiation light that irradiates
the analyte 20. The irradiation light includes component light of R
component, G component, and B component.

[0046]The light guide 120 is formed by an optical fiber for example. The
light guide 120 guides light generated in the light irradiation section
150 to the tip 102 of the endoscope 100. The light guide 120 may include
an outlet 124 provided on the tip 102. The light generated in the light
irradiation section 150 is irradiated onto the analyte 20 through the
outlet 124.

[0047]The image capturing section 110 receives at least one of light
emitted from the luminescence substance and reflection light resulting
from reflection of the irradiation light at the object. The image
generating section 140 generates an image by processing light reception
data acquired from the image capturing section 110. The output section
180 outputs the image generated by the image generating section 140.

[0048]The control section 105 includes an image capturing control section
160 and a light emission control section 170. The image capturing control
section 160 controls image capturing of the image capturing section 110.
The light emission control section 170 controls the light irradiation
section 150 in response to the control by the image capturing control
section 160. For example, when the image capturing section 110 captures
an image of each component light of infrared light, R component, G
component, and B component by time division, the light emission control
section 170 controls light irradiated by the light irradiation section
150 onto the analyte 20, so that the timing of irradiation of each
component light is synchronized with the image capturing timing.

[0049]FIG. 2 shows an exemplary configuration of the image capturing
section 110. The image capturing section 110 includes an objective lens
112, an image capturing device 210, a spectral filter 220, and a light
reception side excitation light cutting filter 230. The image capturing
device 210 includes a plurality of first light receiving elements 251
including a first light receiving element 251a, a plurality of second
light receiving elements 252 including a second light receiving element
252a and a second light receiving element 252b, and a plurality of third
light receiving elements 253 including a third light receiving element
253a.

[0050]The function and the operation of the constituting elements of the
image capturing section 110 are explained as follows. In the following
explanation, the plurality of first light receiving elements 251 are
occasionally collective referred to as a first receiving element 251, the
plurality of second light receiving elements 252 are occasionally
collectively referred to as a second light receiving element 252, and the
plurality of third light receiving elements 253 are occasionally
collectively referred to as a third light receiving element 253. In
addition, the plurality of first light receiving elements 251, the
plurality of second light receiving elements 252, and the plurality of
third light receiving elements 253 are occasionally collectively and
simply referred to as a light receiving element.

[0051]The first light receiving element 251, the second light receiving
element 252, and the third light receiving element 253 receive light from
a subject provided via the objective lens 112. Specifically, the first
light receiving element 251 receives light of a first wavelength region.
The second light receiving element 252 receives light of a second
wavelength region. The third light receiving section 253 receives light
of a third wavelength region that is different from the second wavelength
region.

[0052]The first wavelength region, the second wavelength region, and the
third wavelength region are mutually different wavelength regions,
indicating that each of them is a wavelength region that is not included
in any of the other wavelength regions. The first light receiving element
251, the second light receiving element 252, and the third light
receiving element 253 are arranged two dimensionally in a predetermined
pattern.

[0053]The spectral filter 220 includes a plurality of filter elements that
transmit one of light of the first wavelength region, light of the second
wavelength region, and light of the third wavelength region. Each filter
element is aligned two dimensionally in association with each of the
first light receiving element 251, the second light receiving element
252, and the third light receiving element 253. Each light receiving
element receives light transmitted through the corresponding filter
element. In this way, the first light receiving element 251, the second
light receiving element 252, and the third light receiving element 253
receive light of a different wavelength region from each other.

[0054]The light reception side excitation light cutting filter 230 is
provided at least between the subject and the second light receiving
element 252 and the third light receiving element 253, and cuts light of
the wavelength region of excitation light. The second light receiving
element 252 and the third light receiving element 253 receive light
reflected from the subject via the excitation light cutting filter. In
this way, the second light receiving element 252 and the third light
receiving element 253 are prevented from receiving the excitation light
reflected from the subject.

[0055]The light reception side excitation light cutting filter 230 may cut
light of the wavelength region of excitation light and light of the
specific wavelength region. In this case, the second light receiving
element 252 and the third light receiving element 253 are prevented from
receiving luminescence light from a subject.

[0056]Note that the light reception side excitation light cutting filter
230 may be provided between the subject and the second light receiving
element 252. In this case, the light reception side excitation light
cutting filter 230 transmits luminescence light.

[0057]Just as the spectral filter 220, the light reception side excitation
light cutting filter 230 may include filter elements aligned two
dimensionally in association with the first light receiving element 251,
the second light receiving element 252, and the third light receiving
element 253 respectively. The filter element to provide light to the
first light receiving element 251 cuts light of the wavelength region of
excitation light, and transmits light of the first wavelength region and
the specific wavelength region. The filter element to provide light to
the second light receiving element 252 cuts light of the wavelength
region of excitation light and light of the specific wavelength region,
and at least transmits light of the second wavelength region. The filter
element to provide light to the third light receiving element 253 cuts
light of the wavelength region of excitation light and light of the
specific wavelength region, and at least transmits light of the third
wavelength region.

[0058]The image generating section 140 determines the pixel value of one
pixel based at least on the amount of light received by the first light
receiving element 251a, the second light receiving element 252a, the
second light receiving element 252b, and the third light receiving
element 253a. That is, one pixel element is formed by a two dimensional
alignment structure of the first light receiving element 251a, the second
light receiving element 252a, the second light receiving element 252b,
and the third light receiving element 253a, and a plurality of pixel
elements are formed by a two dimensional alignment of such pixel element
alignment. Note that the light receiving elements may be aligned in any
different manner from the alignment structure shown in the present
drawing.

[0059]FIG. 3 shows an exemplary spectral sensitivity characteristic of a
light receiving element, and an exemplary spectral reflectivity of a
surface layer of a living organism that is one example of a target of
which the image is to be captured. The line 330, the line 310, and the
line 320 show the spectral reflectivity distribution of the first light
receiving element 251, the second light receiving element 252, and the
third light receiving element 253, respectively. The line 340 shows an
exemplary spectral reflectivity of a gastrocolic membrana mucosa of which
the image is to be captured.

[0060]As an example, the first light receiving element 251 is sensitive to
the light of a wavelength in the vicinity of 650 nm to which no other
light receiving element is sensitive. In addition, the second light
receiving element 252 is sensitive to the light of a wavelength in the
vicinity of 450 nm to which no other light receiving element is
sensitive. In addition, the third light receiving element 253 is
sensitive to the light of a wavelength in the vicinity of 550 nm to which
no other light receiving element is sensitive.

[0061]The first light receiving element 251 is able to receive light of an
infrared light region (e.g., 810 nm) which is an example of the specific
wavelength region, due to the characteristics of the light reception side
excitation light cutting filter 230 and of the spectral filter 220.
However, the explanation here is confined to a case where the image
capturing system 10 is operated by using the light of a visible light
region. A case where the image capturing system 10 is operated by using
the light of an infrared light region (e.g., 810 nm) is explained in
connection with FIGS. 9 and 10.

[0062]In this way, the first light receiving element 251, the second light
receiving element 252, and the third light receiving element 253
respectively receive light of R component, light of B component, and
light of G component. Note that the first light receiving element 251,
the second light receiving element 252, and the third light receiving
element 253 may be an image capturing element such as CCD and CMOS, for
example. The first light receiving element 251, the second light
receiving element 252, and the third light receiving element 253 have a
spectral sensitivity characteristic shown by the line 330, the line 310,
and the line 320, respectively, due to a combination of the spectral
transmission of the light reception side excitation light cutting filter
230, the spectral transmission of the filter element included in the
spectral filter 220, and the spectral sensitivity of the image capturing
element itself.

[0063]The filter element, which includes the filter element included in
the spectral filter 220 and the light reception side excitation light
cutting filter 230, for supplying light received by the first light
receiving element 251 transmits light of a first partial wavelength
region (R1) and light of a third partial wavelength region (R2). Note
that the filter element functions as a first spectral filter of the
present invention. Note that the filter element, which includes the
filter element included in the spectral filter 220 and the light
reception side excitation light cutting filter 230, for supplying light
received by the second light receiving element 252 transmits light of a
second partial wavelength region (B1) and light of a fourth partial
wavelength region (B2). Note that the filter element functions as a
second spectral filter of the present invention. Note that the filter
element, which includes the filter element included in the spectral
filter 220 and the light reception side excitation light cutting filter
230, for supplying light received by the third light receiving element
253 transmits light of a fifth partial wavelength region (G1) and light
of a sixth partial wavelength region (G2).

[0064]As an example, the first partial wavelength region (R1) may be
600-630 nm, and the third partial wavelength region (R2) may be 570-600
nm. The second partial wavelength region (B1) may be 440-470 nm, and the
fourth partial wavelength region (B2) may be 470-500 nm. The fifth
partial wavelength region (G1) may be 500-530 nm, and the sixth partial
wavelength region (G2) may be 530-570 nm.

[0065]FIG. 4 shows an exemplary configuration of a light irradiation
section 150. The light irradiation section 150 includes a light emission
section 410 and a light source filter 420. The light emission section 410
emits light of a wavelength region that includes a first wavelength
region, a second wavelength region, a third wavelength region, a fifth
partial wavelength region, and a sixth partial wavelength region. Note
that one example of the light emission section 410 in the present
embodiment is a xenon lamp.

[0066]FIG. 5 shows an exemplary configuration of a light source filter
420. FIG. 5 shows a configuration when the light source filter 420 is
viewed in the direction of light irradiated onto the light source filter
420 from the light emission section 410. The light source filter 420
includes an irradiation light filter 520 and an irradiation light filter
510. Note that the light emission control section 170 rotates the light
source filter 420 on a plane substantially vertical to the direction in
which light emitted from the light emission section 410 travels, with its
rotation center being the central axis of the light source filter 420.

[0067]The irradiation light filter 510 cuts off the light of the third
partial wavelength region, the fourth partial wavelength region, and the
sixth partial wavelength region, and transmits the light of the first
partial wavelength region, the light of the second partial wavelength
region, and the fifth partial wavelength region. The irradiation light
filter 520 cuts off the light of the first partial wavelength region, the
light of the second partial wavelength region, and the fifth partial
wavelength region, and transmits the light of the third partial
wavelength region, the light of the fourth partial wavelength region, and
the sixth partial wavelength region. Note that the light from the light
emission section is guided toward a position out of the central axis of
the light source filter 420.

[0068]Accordingly, at the timing at which the light from the light
emission section 410 is guided toward the irradiation light filter 510,
the light of the third partial wavelength region, the light of the fourth
partial wavelength region, and the light of the sixth partial wavelength
region, from among the light from the light emission section 410, are cut
off by the irradiation light filter 510, and the light of the first
partial wavelength region, the light of the second partial wavelength
region, and the light of the fifth partial wavelength region are
transmitted through the irradiation light filter 510. Accordingly, at
this timing, the light of the first partial wavelength region, the light
of the second partial wavelength region, and the light of the fifth
partial wavelength region are irradiated onto the subject.

[0069]At the timing at which the light from the light emission section 410
is guided towards the irradiation light filter 520, the light of the
first partial wavelength region, the light of the second partial
wavelength region, and the light of the fifth partial wavelength region,
from among the light from the light emission section 410, are cut off by
the irradiation light filter 510, and the light of the third partial
wavelength region, the light of the fourth partial wavelength region, and
the light of the sixth partial wavelength region are transmitted through
the irradiation light filter 520. Accordingly, at this timing, the light
of the third partial wavelength region, the light of the fourth partial
wavelength region, and the light of the sixth partial wavelength region
are to be irradiated onto the subject.

[0070]Note that the image capturing section 110 receives irradiated light
reflected from the analyte 20, at the timing at which the light of the
first partial wavelength region, the light of the second partial
wavelength region, and the light of the fifth partial wavelength region,
being visible light, are irradiated, in response to the control by the
image capturing control section 160. Then, the image generating section
140 generates a first visible light image based on the amount of light
received by the image capturing section 110. Note that the first visible
light image may be an example of the first image in the present
invention.

[0071]In addition, the image capturing section 110 receives irradiated
light reflected from the analyte 20, at the timing at which the light of
the third partial wavelength region, the light of the fourth partial
wavelength region, and the light of the sixth partial wavelength region,
being visible light, are irradiated, in response to the control by the
image capturing control section 160. The image generating section 140
generates a second visible light image based on the amount of the light
of the first partial wavelength region, the light of the second partial
wavelength region, and the reflected light of the fifth partial
wavelength region, in addition to the amount of the light of the third
partial wavelength region, the light of the fourth partial wavelength
region, and the light of the sixth partial wavelength region having been
received by the image capturing section 110. Note that the second visible
light image may be an example of the second image in the present
invention.

[0072]FIG. 6 shows an example of an image capturing timing of the image
capturing section 110 and an image generated by the image generating
section 140. The image capturing control section 160 controls the image
capturing section 110 to perform image capturing at the time t600, the
time t601, the time t602, the time t603, . . . . In addition, according
to the timing control by the image capturing control section 160, the
light emission control section 170 controls the light emitted from the
light emission section 410 to irradiate the subject via the irradiation
light filter 510, at the first timing including the time t600 and the
time t602. In this way, the light emission control section 170 controls
the light emission section 410 through the irradiation light filter 510
to emit the light of the first partial wavelength region, the light of
the second partial wavelength region, and the fifth partial wavelength
region towards an subject, by transmitting the light from the light
emission section 410. In the present invention, the light of the first
partial wavelength region and the light of the second partial wavelength
region may be caused by reflection of the light of the first partial
wavelength region and the light of the second partial wavelength region
at the subject respectively.

[0073]Then, at the first timing, the image capturing control section 160
irradiates the light of the wavelength region that includes the first
partial wavelength region, the second partial wavelength region, and the
fifth wavelength region, to the subject, thereby causing the first light
receiving element 251 to receive the light of the first partial
wavelength region reflected from the subject, and causing the second
light receiving element 252 to receive the light of the second partial
wavelength region reflected from the subject, and causing the third light
receiving element 253 to receive the light of the third partial
wavelength region reflected from the subject. In this way, at the first
timing, the image capturing control section 160 controls the first light
receiving element 251 to receive the light of the first partial
wavelength region from the subject, controls the second light receiving
element 252 to receive the light of the second partial wavelength region
from the subject, and controls the third light receiving element 253 to
receive the light of the third partial wavelength region from the
subject.

[0074]In addition, at the second timing that includes the time t602, the
light emission control section 170 irradiates the light emitted from the
light emission section 410 to the subject via the irradiation light
filter 520, by timing control by the image capturing control section 160.
In this way, at a timing other than a predetermined timing, the light
emission control section 170 controls the light emission section 410 to
emit the light of the third partial wavelength region, the light of the
fourth partial wavelength region, and the light of the sixth partial
wavelength region to the subject, by transmitting the light from the
light emission section 410 through the irradiation light filter 520. In
the present invention, the light of the third partial wavelength region
and the light of the fourth partial wavelength region may be caused by
reflection of the light of the third partial wavelength region and the
light of the fourth partial wavelength region at the subject
respectively.

[0075]Then at the second timing, the image capturing control section 160
controls the first light receiving element 251 to receive the light of
the third partial wavelength region reflected from the subject, controls
the second light receiving element 252 to receive the light of the fourth
partial wavelength region reflected from the subject, and controls the
third light receiving element 253 to receive the light of the fifth
partial wavelength region reflected from the subject.

[0076]In this way, at a predetermined timing, the control section 105
controls, to be caused from the subject, the light of the first partial
wavelength region included in the first wavelength region, the light of
the second partial wavelength region included in the second wavelength
region, and the light of the fifth partial wavelength region included in
the third wavelength region. In addition, at a timing other than the
predetermined timing, the control section 105 controls, to be caused from
the subject, the light of the third partial wavelength region included in
the first wavelength region, the light of the fourth partial wavelength
region included in the second wavelength region, and the light of the
sixth partial wavelength region included in the third wavelength region.

[0077]As explained above, the control section 105 controls the wavelength
region of the light to be received by the first light receiving element
251, the second light receiving element 252, and the third light
receiving element 253, at respective timings. Then, the image generating
section 140 generates an image of a subject, based on the amount of light
received by the light receiving element at respective timings, as
explained below.

[0078]The image generating section 140 generates a first visible light
image 620a based on the amount of light received by the light receiving
element at the timing represented by the time t600. The image generating
section 140 also generates a second visible light image 620b based on the
amount of light received by the light receiving element at the timing
represented by the time t600 and the amount of light received by the
light receiving element at the timing represented by the time t601.

[0079]Specifically, the image generating section 140 generates the first
visible light image 620a, by the amount of light (SR1) received by the
first light receiving element 251 and the amount of light (SB1) received
by the second light receiving element 252 at the timing represented by
the time t600. In addition, the light emission control section 170
controls the light emission section 410 to emit, towards the subject, the
light of the first partial wavelength region that is a longer wavelength
region than the third partial wavelength region, at the timing
represented by the time t600. In addition, the first light receiving
element 251 is able to receive the light of the first wavelength region
that is a longer wavelength region than the second wavelength region and
the third wavelength region. Accordingly, when the first light receiving
element 251 has received the light emitted from the light emission
section 410 after being reflected from the object existing within the
substance, the first light receiving element 251 is able to receive the
light of the longest wavelength region from among the first partial
wavelength region, the second partial wavelength region, the third
partial wavelength region, the fourth partial wavelength region, the
fifth partial wavelength region, and the sixth partial wavelength region.

[0080]For this reason, the first light receiving element 251 is able to
receive light reflected from an object existing at a position deeper from
the surface of the substance. Therefore, the image generating section 140
is able to generate the first visible light image 620a that includes an
image of an object (e.g., blood vessel image 626a) existing at a position
deeper from the surface of the substance, at least based on the light of
the first partial wavelength region received by the first light receiving
element 251 at a predetermined timing.

[0081]In addition, at the timing represented by the time t600, the light
emission control section 170 controls the light emission section 410 to
emit, towards the subject, the light of the second partial wavelength
region and the light of the fifth partial wavelength region being a
shorter wavelength region than the fourth partial wavelength region, at
the timing represented by the time t600. In addition, the second light
receiving element 252 is able to receive the light of the second
wavelength region that is a wavelength region shorter than the first
wavelength region and the third wavelength region. Accordingly, when the
second light receiving element 252 has received the light emitted from
the light emission section 410 after being reflected from the object
within the substance, the second light receiving element 252 is able to
receive the light of the shortest wavelength region from among the first
partial wavelength region, the second partial wavelength region, the
third partial wavelength region, the fourth partial wavelength region,
the fifth partial wavelength region, and the sixth partial wavelength
region.

[0082]For this reason, the first light receiving element 251 cannot
receive the light reflected from an object existing at a deep position,
but is able to receive the light reflected from an object existing at a
position shallower from the surface of the substance. Therefore, the
image generating section 140 can generate a first visible light image
620a that includes an image of an object existing at a position shallow
from the surface of the substance (e.g., blood vessel image 622a and
blood vessel image 624a) at least based on the light of the second
partial wavelength region received by the second light receiving element
252 at a predetermined timing.

[0083]In this way, the image generating section 140 is able to generate
the first image that indicates an object positioned at either a position
shallower from the surface of the substance or a position deeper from the
surface of the substance, at least based on the light of the first
partial wavelength region having received by the first light receiving
element 251 at a predetermined timing and the light of the second partial
wavelength region having received by the second light receiving element
252 at the predetermined timing. Note that in the above-explained
example, the first light receiving element 251 has received light of a
wavelength region longer than the wavelength regions received by the
other light receiving elements, and the second light receiving element
252 has received light of a wavelength region shorter than the wavelength
regions received by the other light receiving elements. However, it is
needless to say that the second light receiving element 252 may receive
light of a wavelength region longer than the wavelength regions received
by the other light receiving elements, and the first light receiving
element 251 may receive light of a wavelength region shorter than the
wavelength regions received by the other light receiving elements.

[0084]The image generating section 140 generates a second visible light
image 620a by the amount of light (SR2) received by the first light
receiving element 251, the amount of light received by the second light
receiving element 252 (SB2), the amount of light received by the third
light receiving element 253 (SG2), at the timing represented by the time
t602, and the aforementioned SR1, SB1, and SG1.

[0085]Specifically, the image generating section 140 adds SR1, SR2, SG1,
SG2, SB1, and SB2 at a predetermined weight to each pixel, to calculate
the amount of light SR for R component for each pixel. Likewise, the
image generating section 140 adds R1, SR2, SG1, SG2, SB1, and SB2 at a
predetermined weight to each pixel, to calculate the amount of light SG
of G component and the amount of light SB of B component for each pixel.
Then the image generating section 140 calculates the second visible light
image 620b based on the calculated SR, SG, and SB.

[0086]Note that the image generating section 140 may also calculate SR,
SG, and SB by calculating SR=SR1+SR2, SB=SB1+SB2, and SG=SG1+SG2. In this
way, the image generating section 140 may generate the second visible
light image based on the summation between the amount of light of the
first partial wavelength region received by each first light receiving
element 251 at a predetermined timing and the amount of light of the
third partial wavelength region received by each first light receiving
element 251 at a timing other than the predetermined timing, and based on
the summation between the amount of light of the second partial
wavelength region received by each second light receiving element 252 at
the predetermined timing and the amount of light of the fourth partial
wavelength region received by each second light receiving element 252 at
a timing other than the predetermined timing.

[0087]As explained above, the image generating section 140 generates the
second image that indicates the image of the subject, from the light of
the first partial wavelength region received by the first light receiving
element 251 at the predetermined timing, the light of the third partial
wavelength region received by the first light receiving element 251 at a
timing other than the predetermined timing, the light of the second
partial wavelength region received by the second light receiving element
252 at the predetermined timing, as well as the light of the fourth
partial wavelength region received by the second light receiving element
252 at a timing other than the predetermined timing.

[0088]In addition, the image generating section 140 may generate a
composite image by combining the first visible light image 620a and the
second visible light image 620b. In this operation, the image generating
section 140 may generate a composite image by overlapping the first
visible light image onto the second visible light image with an emphasis
on the first visible light image. For example, the image generating
section 140 may generate a composite image by overlapping the pixel value
emphasized image of the first visible light image 620a onto the second
visible light image 620b. The output section 180 may output the first
visible light image and the second visible light image generated by the
image generating section 140 in association with each other.

[0089]As explained above, the image generating section 140 generates the
first visible light image by combining at least one of the light of the
first partial wavelength region received by the first light receiving
element 251 at a predetermined timing, the light of the third partial
wavelength region received by the first light receiving element 251 at a
timing other than the predetermined timing, the light of the second
partial wavelength region received by the second light receiving element
252 at the predetermined timing, the light of the fourth partial
wavelength region received by the second light receiving element 252 at a
timing other than the predetermined timing, the light of the fifth
partial wavelength region received by the third light receiving element
253 at the predetermined timing, and the light of the sixth partial
wavelength region received by the third light receiving element 253 at a
timing other than the predetermined timing. The image generating section
140 also generates the second visible light image by a combination
different from the combination selected for the first visible light
image.

[0090]The image capturing system 10 of the present embodiment is able to
provide a first visible light image in which the blood vessels both on
the surface as well as deeper from the surface are emphasized, and a
second visible light image 620b for surface observation. For this reason,
when the image capturing system 10 is actually applied, for example when
a doctor performs operation or the like while observing the image
displayed on the output section 180, he or she has a chance of
recognizing the blood vessels existing deep inside that are difficult to
locate from surface observation. In addition, it is an advantage to allow
a doctor to perform operation or the like by referring to the image in
which the blood vessels are emphasized.

[0091]In addition, the image capturing system 10 is able to receive light
from a plurality of partial wavelength regions for each of the wavelength
regions received by the light receiving elements, thereby enabling to
calculate the reflectivity of the light from the subject for each partial
wavelength region. For example, the image capturing system 10 is able to
calculate the reflectivity of the light from the subject for each partial
wavelength region based on the amount of emitted light and the amount of
received light for each of the partial wavelength regions indicated by
B1, B2, G1, G2, R2, and R1 shown in FIG. 3.

[0092]In addition, the image capturing system 10 is able to calculate the
reflectivity of each partial wavelength region for each pixel. In
addition, the image capturing system 10 can identify a position of an
abnormal portion of a gastrocolic membrana mucosa, by comparing the
spectral reflectivity of the membrane mucosa such as shown by the line
340 in FIG. 3 to the reflectivity for each pixel.

[0093]In addition, the image capturing system 10 calculates the absorption
ratio of each partial wavelength region from the reflectivity of each
partial wavelength region. Also based on the absorption ratio, the image
capturing system 10 may be able to calculate a component included in the
analyte 20 based on the absorption ratio. For example, the image
capturing system 10 can sometimes calculate the ratio of the components
in the blood, by irradiating light of wavelength regions different in
absorption ratio in various components in the blood such as oxygenated
hemoglobin and reduced hemoglobin, from the light irradiation section
150, thereby enabling to calculate the oxygen concentration in the blood
or the like.

[0094]In addition, the control section 105 may control the light
irradiation section 150 to irradiate the light of a partial wavelength
region of a narrow bandwidth that has a characteristic reflectivity in
the spectral reflectivity for a particular type of subject. The image
capturing system 10 according to the present embodiment is able to
control the wavelength region of the light received by the light
receiving element that has a unique spectral sensitivity characteristic,
by controlling the wavelength region irradiated by the light irradiation
section 150, thereby enabling to reduce the size of the endoscope 100.

[0095]FIG. 7 shows an exemplary block configuration of the image
generating section 140. FIG. 6 deals with a case of combining the first
visible light image 620a and the first visible light image 620b, assuming
that there is substantially no factor that causes the temporal change in
image, such as a motion of the tip 102 of the endoscope 100 or the motion
of the analyte 20 for the purpose of facilitating explanation. In this
combining operation, it is possible that the object position be different
between the first visible light image 620a and the first visible light
image 620b, when there actually is a motion of the tip 102 of the
endoscope 100 or the motion of the analyte 20.

[0096]The present drawing shows the operation and the function of the
image generating section 140 for correcting the effect of the
aforementioned motions to the visible light image, as well as the
configuration of the image generating section 140. The image generating
section 140 includes a motion specifying section 910, a corrected image
generating section 920, and a subject image generating section 930.

[0097]Based on visible light images at a plurality of timings, the motion
specifying section 910 specifies the motion of the object in the images.
Here, the motion of the object includes a motion of the analyte 20
itself, a motion of the tip 102 of the endoscope 100, the temporal change
of the zoon value of the image capturing section 110, and the motion that
causes the temporal change of the image. In addition, the motion of the
tip 102 of the endoscope 100 includes a temporal change in position of
the tip 102 that causes the temporal change of an image capturing
position of the image capturing section 110 and the temporal change in
direction of the tip 102 that causes the temporal change of the image
capturing direction of the image capturing section 110.

[0098]Here, the motion specifying section 910 specifies the motion of the
object based on the visible light images at the time t600 and the time
t601. For example, the motion specifying section 910 may specify the
motion of an object, by matching each extracted object from a plurality
of visible light images.

[0099]The corrected image generating section 920 corrects an image signal
representing the visible light image at the time t601, based on the
motion, thereby generating an image signal representing the visible light
image to be obtained at the time t602. Accordingly, the corrected image
generating section 920 can generate the image of the subject at the time
t602.

[0100]FIG. 8 explains generation of a visible light image in which the
motion is corrected. The visible light image 820a is generated from a
image signal from the first light receiving element 251 and the second
light receiving element 252 at the time t600. In addition, the visible
light image 820c is generated from an image signal from the first light
receiving element 251 and the second light receiving element 252 at the
time t602.

[0101]Here, the motion specifying section 910 specifies the motion based
on the image contents of the visible light image 820a and the visible
light image 820c. Specifically, the motion specifying section 910
extracts objects representing the same subject, from the visible light
image 820a and the visible light image 820c. In the present example, the
motion specifying section 910 extracts the object 850a and the object
850c, from the visible light image 820a and the visible light image 820c,
respectively.

[0102]The motion specifying section 910 calculates the difference in
respective positions of the object 850a and the object 850c. In the
example of the drawing, the motion specifying section 910 calculates the
positional difference Δy between the object 850a and the object
850c, assuming that there is a positional difference in y direction
higher in the image to simplify the explanation. The corrected image
generating section 920 generates the visible light image 830b by shifting
the image 821a in the direction y, by the amount of Δy/2 in
accordance with the calculated positional difference Δy and each
timing of the time t600, the time t601, and the time t602.

[0103]The aforementioned explanation is about specifying the motion using
the visible light image 820. However, the image of each color component
may also be used to specify the motion. Here, the motion specifying
section 910 may use the contrast of the captured image to decide which
image of wavelength to be used for specifying the motion by the motion
specifying section 910. For example, the motion specifying section 910
may prioritize an image having a larger contrast when specifying the
motion. When an image having a microstructure can be used as an object
for motion specification such as when the image of the microstructure of
the surface is clear for example, the motion can be more accurately
specified using the image of B signal (e.g., SB1 image). In
addition, when an image of a concave/convex structure is used as an
object for motion specification such as when the image of the
concave/convex structure on the surface is clear, the motion can be more
accurately specified using the image of G signal (e.g., SG1 image).

[0104]The corrected image generating section 920 may apply a different
amount of correction of motion for each image region in a visible light
image. For example, when the image capturing direction of the image
capturing section 110 is vertical to the surface of a subject, and the
tip 102 of the endoscope 100 moves horizontally with respect to the
surface of the subject, the amount of motion of the object can be
considered to be equal to each image region. However, for example when
the image capturing direction of the image capturing section 110 is not
vertical to the surface of the subject, the amount of motion in an image
region in which a region far from the tip 102 is captured will have a
small amount of motion than in an image region in which a region close to
the tip 102 is captured.

[0105]So that the corrected image generating section 920 calculates the
amount of correction of motion with respect to a visible light image for
each image region, the positional relation between the surface of a
subject and the image capturing section 110 should be known or should be
estimated, by which the amount of correction of motion can be calculated
based on the positional relation and the position of the image region.
Note that the corrected image generating section 920 may acquire a
control value for operating the endoscope 100 for causing a temporal
change in image, such as a control value for controlling the position or
the direction of the tip 102 and a control value for controlling a zoom
value of the image capturing section 110, so as to calculate the amount
of correction of motion with respect to the visible light image based on
the control value.

[0106]The motion specifying section 910 may alternatively calculate the
motion of an object for each image region. The corrected image generating
section 920 may calculate the amount of correction of motion with respect
to the image in each image region based on the motion of the object for
each image region.

[0107]Note that when specifying the motion for each image region, the
motion specifying section 910 may decide which image of wavelength to be
used in specifying the motion for each image region. The motion
specifying section 910 calculates the contrast for each image for each
image region, for example. Then the motion specifying section 910 may
select images of different wavelengths of which a larger contrast is
calculated over the other images for respective image regions, to use the
selected images in specifying the motion of the object.

[0108]Note that in the above example, the visible light image 820a and the
visible light image 820c are used to specify the motion. However, the
motion specifying section 910 may use the visible light image 820a and
the visible light image generated by the light of the same wavelength
region obtained prior to the time t600.

[0109]When the display of a visible light image can be delayed to some
extent, the motion specifying section 910 may specify the motion from
images obtained at a plurality of timings including a timing around the
time t601 that is a targeted time at which the visible light image in
which the motion is corrected is to be generated. The accuracy in
specifying the motion can sometimes be enhanced by utilizing images of
later timings. Note that the motion specifying section 910 may specify
the motion by using visible light images (or images of each color
component) captured at three or more timings.

[0110]The subject image generating section 930 may generate a second
visible light image which is an example of a subject image of the present
invention, by combining the visible light image 830b and the visible
light image captured at the time t601. Accordingly, the second visible
light image in which the motion is corrected can be obtained by utilizing
visible light images captured at different timings.

[0111]The aforementioned example deals with the operation of the image
generating section 140 when correcting the motion for generating the
second visible light image at the time t601. The corrected image
generating section 920 may also generate a first visible light image in
which the motion is corrected based on the motion specified by the motion
specifying section 910. The subject image generating section 930 may
output, to the output section 180, a combined image of the first visible
light image in which the motion is corrected and the second visible light
image in which the motion is corrected.

[0112]In addition, the aforementioned example deals with the generation of
various visible light images at the time t601. However, the similar
processing can be used to generate various visible light images at the
time t602. For example, the motion specifying section 910 may use the
visible light images (or images of respective color components) obtained
at the time t601 and the time t603 respectively in specifying the motion.
The corrected image generating section 920 may correct various visible
light images obtained at the time t601, according to the motion.

[0113]As explained above in connection with FIGS. 7 and 8, the motion
specifying section 910 specifies the motion of an object on an image
among a plurality of timings, based on the light of the first partial
wavelength region received by the first light receiving element 251 at a
plurality of timings including the predetermined timing, as well as the
light of the second partial wavelength region received by the second
light receiving element 252 at the plurality of timings. The corrected
image generating section 920 generates a corrected image which is an
image of a subject generated by the light of the first partial wavelength
region and the light of the second partial wavelength region at a timing
other than the predetermined timing, based on the light of the first
wavelength region received by the first light receiving element 251 at
the predetermined timing and the light of the second wavelength region
received by the second light receiving element 252 at the first timing.
The subject image generating section 930 may generate a second image
based on the corrected image and an image generated by the light of the
third partial wavelength region received by a plurality of first light
receiving elements at a timing other than the predetermined timing, and
the light of the fourth partial wavelength region received by a plurality
of second light receiving elements at a timing other than the
predetermined timing.

[0114]FIG. 9 shows an example of a spectral sensitivity characteristic of
a light receiving element and a configuration of the light source filter
420. The following explanation focuses on the differences from the
spectral sensitivity characteristic and the function of the light source
filter 420 in FIGS. 4 and 5. The present drawing shows a spectral
sensitivity characteristic in a wavelength region including a wavelength
region longer than the wavelength region shown in FIG. 3. As shown in
this drawing, the first light receiving element 251 can receive light in
an infrared region (e.g., 810 nm) which is one example of the specific
wavelength region.

[0116]Therefore, at the timing at which the light from the light emission
section 410 is guided toward the irradiation light filter 730, from among
the light from the light emission section 410, the excitation light, the
light of the second partial wavelength region, and the light of the fifth
partial wavelength region are transmitted through the irradiation light
filter 710 to irradiate the subject. At the timing at which the light
from the light emission section 410 is guided towards the irradiation
light filter 720, from among the light from the light emission section
410, the light of the third partial wavelength region, the light of the
fourth partial wavelength region, and the light of the sixth partial
wavelength region are transmitted through the irradiation light filter
720 to irradiate the subject. At the timing at which the light from the
light emission section 410 is guided towards the irradiation light filter
730, from among the light from the light emission section 410, the light
of the seventh partial wavelength region (R3), the light of the eighth
partial wavelength region (B3), and the light of the ninth partial
wavelength region (G3) are transmitted through the irradiation light
filter 730 to irradiate the subject.

[0117]FIG. 10 shows an example of an image capturing timing of the image
capturing section 110 and an image generated by an image generating
section 140. The image capturing control section 160 controls the image
capturing section 110 to perform image capturing at the time t800, the
time t801, the time t802, the time t803, . . . . By the timing control by
the image capturing control section 160, the light emission control
section 170 irradiates the light emitted from the light emission section
410 onto the subject via the irradiation light filter 710, at the first
timing including the time t800 and the time t803. According to this
arrangement, the excitation light, the light of the second partial
wavelength region, and the light of the fifth partial wavelength region
irradiate the subject.

[0118]The image generating section 140 generates a luminescence light
image 820a at the time t800, based on the amount of luminescence light
received by the first light receiving element 251. Since the excitation
light reaches deeper in a substance than the light of the other partial
wavelength regions, the luminescence light image 820a contains the blood
vessel images 822a and 824a at shallow positions from the surface of the
substance, as well as the blood vessel image 826a at a deep position.

[0119]The light emission control section 170 irradiates the light emitted
from the light emission section 410 via the irradiation light filter 720,
at the time t801, by the timing control by the image capturing control
section 160. Accordingly, the light of the third partial wavelength
region, the light of the fourth partial wavelength region, and the light
of the sixth partial wavelength region irradiate the subject.

[0120]By the timing control by the image capturing control section 160,
the light emission control section 170 irradiates the subject with the
light emitted from the light emission section 410 via the irradiation
light filter 730 at the time t802. Accordingly, the light of the seventh
partial wavelength region (R3), the light of the eighth partial
wavelength region (B3), the light of the ninth partial wavelength region
(G3) irradiate the subject. The image generating section 140 generates
the first visible light image 820b based on the amount of light (SB1)
received by the second light receiving element 252 at the time t800 and
the amount of light (SR2) received by the first light receiving element
251 at the time t801. Just as the first visible light image 620b, the
first visible light image 820b contains the image of an object existing
at a deeper position from the surface of the substance (e.g., the blood
vessel image 826b) and the image of an object existing at a shallow
position from the surface of the substance (e.g., the blood vessel image
822b and the blood vessel image 624b).

[0121]At the timing represented by the time t800, the image generating
section 140 generates the second visible light image 820c based on the
amount of light received by the light receiving elements other than the
first light receiving element 251 at the timing represented by the time
t800 (SB1 and SG1), the amount of light received by each light receiving
element at the timing represented by the time t801 (SB2, SG2, and SR2),
and the amount of light received by each light receiving element at the
timing represented by the time t803 (SB3, SG3, and SR3). Note that the
image generating section 140 can generate the second visible light image
820c just as in the method explained with reference to FIG. 6.

[0122]For example, the image generating section 140 is able to generate
the second visible light image 820c, by summing the SB1, SG1, SB2, SG2,
SR2, SB3, SG3, and SR3 by adding thereto a predetermined weight thereby
obtaining the SR, SG, and SB. The second visible light image 820c
contains an image of an object existing at a relatively shallow position
(e.g., blood vessel images 822c and 824c).

[0123]In this way, according to the image capturing system 10 of the
present embodiment, the luminescence light image 820a can be obtained by
the luminescence light of an infrared region caused from the analyte 20
by means of the excitation light of the infrared region. The excitation
light having a longer wavelength than the visible light is hard to be
absorbed by a substance than the visible light. Therefore, the excitation
light enters deeper in the substance than the visible light, to cause the
analyte 20 to generate luminescence light. In addition, the luminescence
light has a wavelength even longer than the wavelength of the excitation
light, and so is easy to reach the surface of the substance. Therefore,
the image capturing system 10 can obtain the blood vessel image of a
depth range wider than the visible light at once.

[0124]In the embodiments explained in connection with FIGS. 9 and 10, the
corrected image generating section 920 is able to generate a first
visible light image in which the motion is corrected and a luminescence
light image, using the similar processing as the processing described in
connection with FIGS. 7 and 8. The subject image generating section 930
may generate a second visible light image by combining visible light
images in which the motion is corrected, or an image in which the second
visible light image is combined with a luminescence light image.

[0125]So far, the embodiments of the present invention have been explained
in a case where the control section 105 causes light of a different
wavelength region from a subject at a different timing. So as to obtain
an image of light of a different wavelength region, the main wavelength
component in a light spectrum from a subject should be in a predetermined
wavelength region, and a certain spectral intensity can remain in the
other wavelength regions. For example, the light from a subject at a
predetermined timing may have a spectral intensity in the third partial
wavelength region and in the fourth partial wavelength region, in
addition to the first partial wavelength region and the second partial
wavelength region. If light from a subject at a predetermined timing has
a spectral intensity mainly in the first partial wavelength region and in
the second partial wavelength region, the image of the first partial
wavelength region and the second partial wavelength region can be
substantially generated.

[0126]In this way, the control section 105 may cause light of a different
spectrum from a subject at a different timing, in each of the first
wavelength region and the second wavelength region. For example, the
control section 105 may control the light irradiation section 150 to
irradiate light that causes the ratio of the spectral intensity of the
third partial wavelength region with respect to the spectral intensity of
the first partial wavelength region in the light from the subject to be
larger at a timing other than a predetermined timing than at the
predetermined timing. More specifically, the control section 105 may
cause the light irradiation section 150 to irradiate light that causes
the spectral intensity of the first partial wavelength region to be
larger than the spectral intensity of the third partial wavelength region
at a predetermined timing, and to irradiate light that causes the
spectral intensity of the third partial wavelength region to be larger
than the spectral intensity of the first partial wavelength region at a
timing other than the predetermined timing.

[0127]Likewise, the control section 105 may control the light irradiation
section 150 to irradiate light that causes the ratio of the spectral
intensity of the fourth partial wavelength region with respect to the
spectral intensity of the second partial wavelength region in the subject
light to be larger at a timing other than the predetermined timing than
at the predetermined timing. More specifically, the control section 105
may cause the light irradiation section 150 to irradiate light that
causes the spectral intensity of the second partial wavelength region to
be larger than the fourth partial wavelength region at the predetermined
timing, and to irradiate light that causes the spectral intensity of the
fourth partial wavelength region to be larger than the spectral intensity
of the second partial wavelength region at a timing other than the
predetermined timing.

[0128]The image generating section 140 may generate a first image by a
combination of light of a first spectrum from a subject received by the
first light receiving element 251 at the predetermined timing, light of a
second spectrum from the subject received by the second light receiving
element 252 at the predetermined timing, light of a third spectrum from
the subject received by the first light receiving element 251 at a timing
other than the predetermined timing, and light of a fourth spectrum from
the subject received by the second light receiving element 252 at a
timing other than the predetermined timing. The image generating section
140 may also generate a second image by a combination different from the
aforementioned combination to generate the first image.

[0129]In connection with FIGS. 4, 5, and 9, described is the operation to
temporarily control the spectrum of the irradiation light emitted from
the light emission section 410 by rotating the light source filter 420 as
an operation of the light irradiation section 150. As another example of
the light irradiation section 150, the light irradiation section 150 does
not have to include a light source filter 420. Specifically, the light
emission section 410 may include a plurality of light emitting elements
emitting a different spectrum of light from each other. The control
section 105 may control light emission at the predetermined timing and at
a timing different from the predetermined timing.

[0130]For example, the light emission section 410 may include a light
emitting element that emits light of a red wavelength region, a light
emitting element that emits a blue wavelength region, a light emitting
element that emits light of a green wavelength region, and a light
emitting element that emits light of an excitation light wavelength
region. An example of light emitting element that emits light of a
visible light region is a semiconductor device such as LED. An example of
light emitting element that emits excitation light is a semiconductor
device such as a semiconductor laser. In addition, the light emitting
element may be a phosphor that emits luminescence light such as
fluorescence by being excited.

[0131]The control section 105 can control the spectrum of light to
irradiate the subject, by controlling the light emission intensity of
each of the plurality of light emitting elements at each timing. Note
that "to control the light emission intensity of each of the plurality of
light emitting elements" includes control to have a different combination
of light emitting elements that emit light at each timing. In addition, a
light emitting element may include a filter for selectively transmitting
light of the specific wavelength region and a light emitter. If this
light emitter emits light and the spectrum of light after being
transmitted through a filter is different for each filter, the light
emitting elements can be considered as a plurality of light emitting
elements that respectively emit light of a different spectrum from each
other in the present invention.

[0132]Note that a light emitting element can be provided for the tip 102
of the endoscope 100. Note that the light emitting element may emit light
by means of electric excitation, or may emit light by optical excitation.
When the light emitting element emits light by optical excitation, the
light irradiation section 150 includes an excitation section that emits
light for exciting the light emitting element, and the light emitting
element. Here, the light emitting element may emit light of a different
spectrum for a different wavelength of light for excitation. In this
case, the control section 105 may control the spectrum of irradiation
light by controlling the wavelength of light for excitation emitted from
the light emitting section at each timing. The spectrum of light emitted
by each light emitting element by means of the light for excitation may
be different for each light emitting element. In addition, from among the
light for excitation, the light transmitted through the light emitting
element may be irradiated onto the subject as irradiation light.

[0133]FIG. 11 shows an exemplary hardware configuration of a computer 1500
that functions as an image capturing system 10. The image capturing
system 10 according to the present embodiment is provided with a CPU
peripheral section, an input/output section, and a legacy input/output
section. The CPU peripheral section includes a CPU 1505, a RAM 1520, a
graphic controller 1575, and a display apparatus 1580 connected to each
other by a host controller 1582. The input/output section includes a
communication interface 1530, a hard disk drive 1540, and a CD-ROM drive
1560, all of which are connected to the host controller 1582 by an
input/output controller 1584. The legacy input/output section includes a
ROM 1510, a flexible disk drive 1550, and an input/output chip 1570, all
of which are connected to the input/output controller 1584.

[0134]The host controller 1582 is connected to the RAM 1520 and is also
connected to the CPU 1505 and the graphic controller 1575 accessing the
RAM 1520 at a high transfer rate. The CPU 1505 operates to control each
section based on programs stored in the ROM 1510 and the RAM 1520. The
graphic controller 1575 obtains image data generated by the CPU 1505 or
the like on a frame buffer provided inside the RAM 1520 and displays the
image data in the display apparatus 1580. Alternatively, the graphic
controller 1575 may internally include the frame buffer storing the image
data generated by the CPU 1505 or the like.

[0135]The input/output controller 1584 connects the communication
interface 1530 serving as a relatively high speed input/output apparatus,
the hard disk drive 1540, and the CD-ROM drive 1560 to the host
controller 1582. The communication interface 1530 communicates with other
apparatuses via a network. The hard disk drive 1540 stores the programs
and data used by the CPU 1505 in the image capturing system 10. The
CD-ROM drive 1560 reads the programs and data from a CD-ROM 1595 and
provides the read programs and data to the hard disk drive 1540 via the
RAM 1520.

[0136]Furthermore, the input/output controller 1584 is connected to the
ROM 1510, and is also connected to the flexible disk drive 1550 and the
input/output chip 1570 serving as a relatively low speed input/output
apparatus. The ROM 1510 stores a boot program executed when the image
capturing system 10 starts up, a program relying on the hardware of the
image capturing system 10, and the like. The flexible disk drive 1550
reads programs or data from a flexible disk 1590 and supplies the read
programs or data to the hard disk drive 1540 via the RAM 1520. The
input/output chip 1570 is connected to a variety of input/output
apparatuses via the flexible disk drive 1550, and a parallel port, a
serial port, a keyboard port, a mouse port, or the like, for example.

[0137]A communication program supplied to the hard disk drive 1540 via the
RAM 1520 is provided by a user in a state where it is stored in a storage
medium, such as the flexible disk 1590, the CD-ROM 1595, or an IC card.
The communication program is read from the recording medium, installed
via the RAM 1520 to the hard disk drive 1540 in the image capturing
system 10, and is executed by the CPU 1505. The communication program
installed to the image capturing system 10 to be executed acts on the CPU
1505 to cause the image capturing system 10 to function as the image
capturing section 110, the image generating section 140, the output
section 180, the control section 105, and the light irradiation section
150 explained with reference FIGS. 1-10.

[0138]Although some aspects of the present invention have been described
by way of exemplary embodiments, it should be understood that those
skilled in the art might make many changes and substitutions without
departing from the spirit and the scope of the present invention which is
defined only by the appended claims.